Packaging material and manufacturing method thereof

Abstract

To provide a packaging material excellent in wet friction resistance, heat resistance, releasability, water vapor barrier, and heat sealability.SOLUTION: A packaging material has a heat-seal layer, a paper substrate, a printed layer and a surface protection layer in this order, where the surface protection layer contains a rosin resin and at least one selected from the group consisting of acrylic resins and cellulose-based resins. A method for manufacturing a packaging material comprising a heat-seal layer, a paper substrate, a printed layer and a surface protection layer in this order comprises the steps of: printing a printing ink on one surface of the paper substrate to form the printed layer; printing, onto the printed layer, an overcoat agent containing an aqueous rosin resin and at least one selected from the group consisting of acrylic resins and cellulose-based resins, so as to form the surface protection layer; and applying a heat sealant to the other surface of the paper substrate to form the heat-seal layer.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a packaging material and a method for producing the same. [Background technology]

[0002] In recent years, it has become common for product packages and other packaging materials (packages) to be provided with a printed layer or surface protection. The printed layer imparts design, beauty, and a sense of luxury, while the surface protection layer protects the packaging material from physical contact, making them of great industrial value.

[0003] Generally, many packages are made of laminated packaging materials that mainly use plastic films. In recent years, packaging materials have been converted to biomass in order to be environmentally friendly. For example, Patent Document 1 describes an invention of a laminated packaging material consisting of a base material, a printing layer, an adhesive layer, and a sealant layer, in which biomass resin is used in the printing layer and the adhesive layer. However, laminated packaging materials have a low biomass effect because they use a large amount of plastic film, so there is a demand for paper-based biomass packaging materials with the aim of being environmentally friendly and reducing the amount of plastic used, and technology has been developed in recent years. Furthermore, there is a demand for the use of biomass ink in printing inks, etc.

[0004] For example, as an example of using a paper base material as a part of a packaging material, Patent Document 2 describes a heat-sealed paper containing a water-dispersible binder in the heat-sealed layer and having a pulp recovery rate of 85% or more after re-separation. However, there is no mention of an example of printing or the like using the heat-sealed paper. In addition, for example, Patent Document 3 describes an aqueous flexo ink composition using a rosin resin emulsion, but does not describe an embodiment as a paper-based packaging material. Therefore, a paper-based packaging material that satisfies the water friction resistance, heat resistance, and other issues expected of a paper-based packaging material has not yet been found. In addition, in order to improve the practicality of packaging materials using paper base materials and biomass inks, it is necessary to improve the releasability, water vapor barrier property, and heat sealability required for paper-based packaging materials. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-051796 A [Patent Document 2] Patent Publication No. 2022-168003 [Patent Document 3] JP 2019-108529 A Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a packaging material that is excellent in water friction resistance, heat resistance, releasability, water vapor barrier property, and heat sealability. [Means for solving the problem]

[0007] As a result of extensive research into the above problems, the present inventors have found that the above problems can be solved by using the packaging material described below, and have thus completed the present invention.

[0008] That is, the present invention provides: A packaging material having a heat seal layer, a paper base material, a printing layer, and a surface protective layer in this order, The present invention relates to a packaging material, wherein the surface protective layer contains at least one resin selected from the group consisting of an acrylic resin and a cellulose-based resin, and a rosin resin.

[0009] The present invention relates to the packaging material, wherein the surface protective layer has a 60 degree gloss value of 60 or less, as measured by the method described in JIS Z8741:1997.

[0010] The present invention relates to the packaging material, wherein a mass ratio of the acrylic resin and the cellulose-based resin to the rosin resin is from 90:10 to 30:70.

[0011] The present invention relates to the packaging material, wherein the heat seal layer contains a polyethylene-based resin.

[0012] The present invention relates to the packaging material, wherein the polyethylene-based resin comprises at least one selected from the group consisting of ethylene-vinyl acetate copolymer resins and ethylene-acrylic copolymer resins.

[0013] The present invention further relates to said packaging material, comprising a barrier layer.

[0014] The present invention relates to the packaging material, wherein the printed layer contains at least one resin selected from the group consisting of a cellulose-based resin, an acrylic resin, and a styrene-maleic acid copolymer resin.

[0015] The present invention relates to the packaging material, wherein the printed layer contains a sugar-derived resin and / or a rosin resin.

[0016] The present invention relates to a packaging bag formed from the packaging material.

[0017] The present invention relates to a method for producing a packaging material having a heat seal layer, a paper base material, a printing layer, and a surface protective layer in this order, comprising: The present invention relates to a method for producing a packaging material, comprising the steps of: printing a printing ink on one side of a paper base material to form a printed layer; printing an overcoat agent containing at least one resin selected from the group consisting of acrylic resins and cellulose-based resins and an aqueous rosin resin on the printed layer to form a surface protective layer; and applying a heat seal agent to the other side of the paper base material to form a heat seal layer.

[0018] The present invention relates to a method for producing the above packaging material, wherein the aqueous rosin resin is neutralized with a basic compound, and the basic compound contains at least one selected from the group consisting of ammonia, an amine compound, and sodium hydroxide. Effect of the Invention

[0019] According to the present invention, it is possible to provide a packaging material that is excellent in water friction resistance, heat resistance, releasability, water vapor barrier property, and heat sealability. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The following describes in detail the embodiments of the present invention. However, the following description of the components is merely an example of an embodiment of the present invention, and the present invention is not limited to these contents as long as it does not deviate from the gist of the present invention.

[0021] In the following description, unless otherwise specified, "parts" refers to "parts by mass" and "%" refers to "% by mass." In addition, the packaging material may be abbreviated simply as "laminate," but this has the same meaning. In the following description of the present invention, "printing ink" refers to ink containing pigments and other colorants for forming a printed layer, and "overcoat agent" refers to a coating agent for forming a surface protective layer that does not contain pigments or other colorants, but does not exclude traces of colorants that have been unintentionally mixed in.

[0022] [Packaging material] The present invention relates to a packaging material having a heat seal layer, a paper base material, a printing layer, and a surface protective layer in this order, the surface protective layer containing at least one resin selected from the group consisting of acrylic resins and cellulose-based resins, and a rosin resin. This configuration improves heat sealability and water friction resistance, and the surface protective layer contains at least one resin selected from the group consisting of acrylic resins and cellulose-based resins, and a rosin resin, improving release properties and heat resistance. The packaging material may further include a barrier layer on the paper base material, and may include an adhesive resin layer for bonding the barrier layer and the paper base material.

[0023] Suitable examples of the layered structure of the packaging material are as follows: In the following examples, " / " indicates the boundary between layers. Heat seal layer / paper base material / printing layer / surface protection layer Heat seal layer / barrier layer / paper base material / printing layer / surface protection layer Heat seal layer / paper base material / barrier layer / printing layer / surface protection layer Heat seal layer / paper base material / printing layer / barrier layer / surface protection layer

[0024] [Surface protective layer] The surface protective layer contains at least one resin selected from the group consisting of acrylic resins and cellulose-based resins, and a rosin resin. In the surface protective layer, the total content of the at least one resin selected from the group consisting of acrylic resins and cellulose-based resins, and the rosin resin is preferably 50% by mass or more, more preferably 70% by mass or more, and particularly preferably 90% by mass or more, based on the total mass of the surface protective layer. When the total content is within the above range, the toughness of the surface protective layer is increased, and the releasability and heat resistance of the packaging material are improved. In the surface protective layer, the mass ratio of the acrylic resin and the cellulose-based resin to the rosin resin is preferably 90:10 to 30:70, and more preferably 90:10 to 50:50. In addition, the thickness of the surface protective layer is preferably 0.3 to 10 μm, more preferably 1 to 7 μm, and even more preferably 3 to 5 μm. The releasability of the packaging material means that when the packaging material is taken out from the rolled up packaging material during printing, the printed layer and / or the surface protective layer does not transfer to the back surface (heat seal layer) of the paper base material.

[0025] The gloss value of the surface protective layer is preferably 60 or less, more preferably 40 or less, and even more preferably 20 or less. When the gloss value of the surface protective layer is within the above range, the water friction resistance is good. The gloss value is a 60 degree gloss value (Gs(60)) measured in accordance with JIS Z 8741:1997. The gloss value mentioned above is different from the gloss (mirror reflection) of a metal layer such as an aluminum vapor deposition layer on the inside of the packaging material. When the surface protective layer contains at least one resin selected from the group consisting of acrylic resins and cellulose-based resins, and a rosin resin, it becomes easy to adjust the gloss value of the surface protective layer to the above range.

[0026] <Acrylic resin contained in the surface protective layer> The acrylic resin is preferably an aqueous resin, and the aqueous resin may be either a water-soluble resin or an aqueous emulsion resin, but is preferably an aqueous emulsion resin. The acrylic resin is preferably a styrene-acrylic copolymer resin. The water-soluble styrene-acrylic copolymer resin refers to a resin in which the acrylic resin itself is dissolved in water alone.

[0027] The acrylic resin preferably has an acid group, and in this case, the acid value is preferably 20 to 200 mgKOH / g, more preferably 30 to 150 mgKOH / g, and even more preferably 80 to 120 mgKOH / g. When the acrylic resin has an acid group and the acid value is within the above range, the releasability and heat resistance of the packaging material are good.

[0028] The weight average molecular weight of the acrylic resin is preferably from 2,000 to 600,000, more preferably from 50,000 to 600,000, and particularly preferably from 70,000 to 600,000.

[0029] The glass transition temperature of the acrylic resin is preferably from -20 to 80°C, more preferably from -10 to 60°C, and further preferably from 0 to 40°C.

[0030] When the weight average molecular weight and glass transition temperature of the acrylic resin are within the above ranges, it is possible to obtain a printing layer that is both strong and flexible, resulting in good releasability and heat resistance.

[0031] The acrylic resin may be a commercially available product, such as X-310, VS-1057, GL-2439, and TS-1316 manufactured by Seiko PMC Corporation, and Joncryl 74J and Joncryl 537E manufactured by BASF.

[0032] <Cellulosic resin contained in surface protective layer> The cellulose resin refers to a resin derived from cellulose. The preferred embodiments are shown below. The weight average molecular weight of the cellulose resin is preferably 5,000 to 100,000, more preferably 10,000 to 70,000. The glass transition temperature is preferably 100°C to 160°C. Examples of the cellulose resin include nitrocellulose, cellulose acetate alkylates such as cellulose acetate propionate and cellulose acetate butyrate, and alkylcelluloses such as hydroxyalkylcellulose and carboxyalkylcellulose. The alkyl group may be, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, or a hexyl group, and the alkyl group may further have a substituent. Among them, cellulose acetate propionate, cellulose acetate butyrate, and nitrocellulose are preferred. Nitrocellulose is particularly preferred. The nitrogen content of nitrocellulose is preferably 10 to 13% by mass.

[0033] <Rosin resin contained in the surface protective layer> The rosin resin is preferably an aqueous resin, and may be either an emulsion or a water-soluble resin. The acid value of the rosin resin emulsion is preferably 80 to 350 mgKOH / g, more preferably 90 to 250 mgKOH / g, and more preferably 100 to 200 mgKOH / g. The rosin resin emulsion is preferably one obtained by finely dispersing a rosin derivative such as a rosin ester in water in the presence of a surfactant. Specific examples of the rosin resin emulsion include Hariestar SK370N manufactured by Harima Chemicals Co., Ltd. The acid value of the water-soluble rosin resin is preferably 80 to 350 mgKOH / g, more preferably 100 to 300 mgKOH / g, more preferably 20 to 270 mgKOH / g, and particularly preferably 150 to 250 mgKOH / g. Specific examples of water-soluble rosin resins include Harima Chemical's Harimac T-80, AS-5, Hariestar MSR-4, Tespol 1150, 1154, and 1158, and Arakawa Chemical's Marquid 31, 32, and 33. However, the water-soluble rosin resin is preferably neutralized with a basic compound, and examples of the basic compound include ammonia and organic amines. Specific examples of the organic amines include alkylamines such as diethylamine, triethylamine, and ethylenediamine, and alkanolamines such as monoethanolamine, ethylethanolamine, diethylethanolamine, diethanolamine, and triethanolamine. The boiling point of the highly volatile amine is preferably 150° C. or less, more preferably 100° C. or less, and even more preferably 50° C. or less. The content of the rosin resin is preferably 10% by mass or more in the solid content of the aqueous printing ink.

[0034] The acid value is the number of milligrams of potassium hydroxide required to neutralize the acidic groups contained in 1 g of resin solid content, and is measured in accordance with JIS K0070.

[0035] The weight average molecular weight (Mw) can be measured, for example, by GPC (gel permeation chromatography). In the case of aqueous resins, the molecular weight can be calculated using polyethylene glycol as a standard substance. The measuring device is a GPC device such as Shodex GPC-401 manufactured by Showa Denko K.K. The column is a Shodex OHpak LB-8 manufactured by Showa Denko K.K. Examples of the detector include RI (differential refractometer), and the measurement temperature is preferably a column temperature of 20 to 50°C. The eluent is 0.1N NaNO 3 The flow rate is 0.2 to 5 mL / min. In the case of oil-based resins, the molecular weight can be calculated using polyethylene glycol as a standard substance, and the measuring device can be a GPC device such as Shodex GPC-104 manufactured by Showa Denko K.K., and the column can be a Shodex LF-404 manufactured by Showa Denko K.K., etc. The detector can be an RI (differential refractometer), and the measurement temperature is preferably a column temperature of 20 to 50° C. The eluent can be tetrahydrofuran, etc., and the flow rate is 0.2 to 5 mL / min.

[0036] The glass transition temperature can be measured, for example, using a differential scanning calorimeter (DSC measuring device, Shimadzu Corporation's "DSC-60A"), and the temperature of the inflection point in the baseline shift can be used as the glass transition temperature. The measurement is preferably performed in a nitrogen atmosphere, with the measurement temperature range being -100 to 200°C and the heating rate being 1 to 5°C / min.

[0037] <Other resins contained in the surface protective layer> The surface protective layer may further contain other resins. Examples of other resins include urethane resins, polylactic acid resins, polyamide resins, castor oil-based resins, vinyl acetate resins, ethylene-vinyl acetate copolymer resins, vinyl acetate resins, styrene-allyl alcohol copolymer resins, styrene-maleic acid copolymer resins, rosin-modified maleic acid resins, dammar resins, and modified resins thereof. These resins may be used alone or in combination of two or more.

[0038] <Additives contained in the surface protective layer> The surface protective layer of the present invention may contain various additives as required, such as dispersants, waxes, extender pigments, leveling agents, defoamers, film-forming assistants, water repellents, and release agents (silicone). Specifically, various additives can be added, such as dispersions of wax resin particles such as polyethylene wax to improve abrasion resistance; extender pigments such as silica, barium sulfate, resin beads, calcium carbonate, and talc to improve drying properties and coating film hiding properties; inorganic particles and adhesive resins (acrylic resin, vinyl acetate resin) to impart anti-slip properties; leveling agents to improve leveling properties; antifoaming agents to impart antifoaming properties; basic compounds such as sodium hydroxide and potassium hydroxide to impart re-solubility; and film-forming aids.

[0039] <Overcoat agent> The surface protective layer is formed by an overcoat agent that contains an acrylic resin and / or a cellulose-based resin, and a rosin resin, and may further contain a liquid medium (organic solvent, water, etc.), additives, etc.

[0040] The solid content of the acrylic resin, cellulose resin, and rosin resin in the overcoat agent is preferably 25 to 100 mass %, more preferably 25 to 75 mass %, and particularly preferably 25 to 45 mass %, of the total mass of the overcoat agent.

[0041] (aqueous medium) The overcoat agent preferably contains an aqueous medium. The aqueous medium refers to a liquid medium in which the water content is 50% by mass or more of the total mass. The aqueous medium preferably contains water as the main component (50% by mass or more), and may further contain a water-soluble organic solvent. Specifically, depending on the printing conditions (speed, plate depth, design, drying temperature), an alcohol-based organic solvent, a glycol-based organic solvent, or the like may be contained as the water-soluble organic solvent. The content of the aqueous medium is preferably 30% by mass or less, and more preferably 20% by mass or less, based on the total amount of the overcoat agent. The water-soluble organic solvent refers to a solvent that is liquid at 25° C. and does not undergo phase separation when mixed 1:1 with water at 25° C. Preferred examples of the water-soluble organic solvent include ethanol, isopropanol, and propylene glycol.

[0042] Examples of the alcohol-based organic solvent include methanol, ethanol, propanol, isopropanol, isobutanol, normal butanol, tertiary butanol, hexanol, octanol, and decanol.

[0043] Examples of the glycol-based organic solvent include ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monooctyl ether, diethylene glycol, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, propylene glycol, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, tripropylene glycol monopropyl ether, tripropylene glycol monobutyl ether, and dibutyl glycol. These may be used alone or in combination of two or more.

[0044] (Organic solvent) The overcoat agent is also preferably a mixture of two or more organic solvents as the main component (50% by mass or more) of the liquid medium. The organic solvent used is preferably a mixed solvent consisting of two or more organic solvents, and known organic solvents such as aromatic organic solvents such as toluene and xylene, ketone organic solvents such as methyl ethyl ketone and methyl isobutyl ketone, ethyl acetate, n-propyl acetate, isopropyl acetate, isobutyl acetate, ester organic solvents, and alcohol organic solvents such as methanol, ethanol, n-propanol, isopropanol, and n-butanol can be used. Among them, organic solvents that do not contain aromatic organic solvents such as toluene and xylene (non-toluene organic solvents) are more preferable, and organic solvents that do not contain aromatic organic solvents and / or ketone organic solvents such as methyl ethyl ketone (hereinafter referred to as "MEK"). In addition, a mixed solvent of an ester organic solvent and an alcohol organic solvent is preferable because it improves printability. A preferred mass ratio of the ester organic solvent and the alcohol organic solvent (ester organic solvent / alcohol organic solvent) is 50 / 50 to 90 / 10.

[0045] <Method of manufacturing the overcoat agent> The overcoat agent can be obtained by feeding a resin solution, in which a resin is dissolved or dispersed in an organic solvent, and a solvent into an agitator equipped with an agitating blade, a rotor, etc., and mixing and stirring the solvent. There is no particular restriction on the stirring speed, and stirring can be performed at 50 to 2000 rpm. In order to improve the handling and coating properties of the overcoat agent, a solvent can also be appropriately added. From the viewpoint of printability and the like, the viscosity of the overcoat agent is preferably 50 to 300 mPa·s.

[0046] <Formation of surface protection layer> The surface protective layer can be formed, for example, by printing an overcoat agent on a printed layer of a laminate in which a printed layer is provided on a substrate, and then removing volatile components. Examples of printing methods include gravure printing and flexographic printing. For example, the overcoat agent is diluted with a diluting solvent to a viscosity and concentration suitable for each printing method, and is supplied to each printing unit alone or in a mixture and applied. Thereafter, the coating is fixed by drying in an oven or the like to obtain a surface protective layer.

[0047] [Print layer] The printing layer is located on the surface of the paper substrate opposite to the surface having the heat seal layer. The printing layer is preferably made of a printing ink containing an aqueous resin or an oil-based resin and a colorant. The aqueous resin refers to a resin that can be dissolved or dispersed in water, and includes a water-soluble resin and an aqueous emulsion resin. Here, the aqueous emulsion resin refers to a resin that is insoluble or poorly soluble in water, but is dispersed and stabilized in water using a surfactant or the like.

[0048] When the printing ink contains an aqueous emulsion resin, the average particle size of the aqueous emulsion resin is preferably 10 to 500 nm, and more preferably 30 to 200 nm. The average particle size is the average particle size in the printing ink.

[0049] The thickness of the printed layer is preferably 0.1 to 10 μm, more preferably 0.3 to 6 μm, and particularly preferably 0.5 to 3 μm. In the present invention, not only a single printed layer but also a layer in which multiple printed layers are overlapped is regarded as the printed layer, and printed layers with different hues can be arbitrarily combined.

[0050] <Binder resin contained in the printing layer> The solid content of the binder resin (aqueous binder resin and / or oil-based binder resin) in the printed layer is preferably 10 to 70 mass % of the total mass of the printed layer, and more preferably 30 to 50 mass %. Examples of the binder resin used include acrylic resin, styrene-acrylic copolymer resin, styrene-maleic acid copolymer resin, urethane resin, polylactic acid resin, polyamide resin, vinyl chloride-acrylic copolymer resin, castor oil resin, rosin resin, vinyl acetate resin, ethylene-vinyl acetate copolymer resin, vinyl acetate resin, styrene-allyl alcohol copolymer resin, rosin-modified maleic acid resin, dammar resin, cellulose resin, and modified resins thereof. In particular, the printing layer preferably contains at least one binder resin selected from the group consisting of cellulose-based resins, acrylic resins, and styrene-maleic acid copolymer resins, and more preferably contains a sugar-derived and / or rosin resin. The sugar-derived resin and / or rosin resin may be, for example, the resins described in JP-A-2021-46522 and JP-A-2019-108529.

[0051] The aqueous binder resin preferably has an acid group, and the acid group that gives the acid value is preferably neutralized with a basic compound. Examples of the acid group include a hydroxyl group, an aldehyde group, a carbonyl group, and a carboxyl group, and the like, and the carboxyl group is preferred. Examples of the basic compound include an amine compound and an alkali metal.

[0052] Examples of the amine compound include ammonia, alkylamines such as diethylamine, triethylamine, and ethylenediamine, and alkanolamines such as monoethanolamine, ethylethanolamine, diethylethanolamine, diethanolamine, and triethanolamine. Examples of the alkali metal include sodium hydroxide and potassium hydroxide. These may be used alone or in combination of two or more.

[0053] (Cellulosic resin) The weight average molecular weight of the cellulose-based resin is preferably 5,000 to 100,000, and more preferably 10,000 to 70,000.The glass transition temperature is preferably 100°C to 160°C.

[0054] When the weight average molecular weight and glass transition temperature of the cellulose-based resin are within the above ranges, it is possible to achieve both toughness and flexibility in the printed layer, resulting in good heat resistance and water friction resistance.

[0055] (Acrylic resin) The acrylic resin is preferably a styrene-acrylic copolymer resin. The acid value of the acrylic resin is preferably 20 to 100 mgKOH / g, more preferably 40 to 80 mgKOH / g. When the acrylic resin has an acid group and the acid value is within the above range, the water friction resistance is good.

[0056] The weight average molecular weight of the acrylic resin is preferably 1,500 to 10,000, and more preferably 4,000 to 30,000.

[0057] The glass transition temperature of the acrylic resin is preferably from 10 to 90°C, and more preferably from 30 to 70°C.

[0058] When the weight average molecular weight and glass transition temperature of the acrylic resin are within the above ranges, it is possible to obtain a printing layer that is both strong and flexible, resulting in good heat resistance and releasability.

[0059] The acrylic resin may be a commercially available product, for example, X-310, VS-1057, GL-2439, or TS-1316 manufactured by Seiko PMC Corporation.

[0060] (Styrene-maleic acid copolymer resin) The styrene-maleic acid copolymer resin preferably has an acid group, and in that case, the acid value is preferably 100 to 180 mgKOH / g, and more preferably 120 to 160 mgKOH / g. When the styrene-maleic acid copolymer resin has an acid group and the acid value is in the above range, the water friction resistance is good.

[0061] The weight average molecular weight of the styrene-maleic acid copolymer resin is preferably 1,500 to 50,000, and more preferably 4,000 to 30,000.

[0062] The glass transition temperature of the styrene-maleic acid copolymer resin is preferably from 40 to 120°C, more preferably from 60 to 100°C.

[0063] When the weight average molecular weight and glass transition temperature of the styrene-maleic acid copolymer resin are within the above ranges, it becomes possible for the printed layer to have both toughness and flexibility, resulting in good heat resistance and release properties.

[0064] As the styrene-maleic acid copolymer resin, commercially available products may be used, for example, M-30 manufactured by Seiko PMC Corporation and Alastar series manufactured by Arakawa Chemical Industries, Ltd. can be used.

[0065] <Colorant contained in the printing layer> The printed layer preferably contains a colorant, and the content of the colorant in the total mass of the printed layer is preferably 1 to 60% by mass, and more preferably 30 to 50% by mass.

[0066] The colorant is preferably a pigment, and either an organic pigment or an inorganic pigment can be used. As the organic pigment, it is preferable to use a pigment made of an organic compound and / or an organic metal complex. As the inorganic pigment, it is preferable to use one containing titanium oxide.

[0067] Specific examples of organic pigments are shown by their Colour Index International (CI) numbers. Preferably, CI Pigment Red 57:1, CI Pigment Red 48:1, CI Pigment Red 48:2, CI Pigment Red 48:3, CI Pigment Red 146, CI Pigment Red 242, CI Pigment Yellow 83, CI Pigment Yellow 14, CI Pigment Orange 64, CI Pigment Orange 38, CI Pigment Orange 34, CI Pigment Orange 13, CI Pigment Yellow 180, CI Pigment Yellow 139, CI Pigment Red 185, CI Pigment Red 122, CI Pigment Red 178, CI Pigment Red 149, CI Pigment Red 144, CI Pigment Red 166, CI Pigment Violet 23, CI Pigment Violet 37, CI Pigment Blue 15, CI Pigment Blue 15:1, CI Pigment Blue 15:2, CI Pigment Blue 15:3, CI Pigment Blue 15:4, CI Pigment Blue 15:6, CI Pigment Green 7, CI Pigment Orange 34, CI Pigment Orange 64, and CI Pigment Black 7. These may be used alone or in combination of two or more.

[0068] (Inorganic pigments) Examples of inorganic pigments include titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, aluminum particles, mica, bronze powder, chrome vermilion, yellow lead, cadmium yellow, cadmium red, ultramarine, Prussian blue, red iron oxide, yellow iron oxide, iron black, titanium oxide, and zinc oxide. Aluminum can be either leafing or non-leafing type, with the non-leafing type being preferred.

[0069] Titanium oxide Titanium oxide may be used in any crystal structure of anatase type, rutile type, or brookite type. Among them, rutile type titanium oxide is preferred because of its good pigment dispersibility. In the industrial production of titanium oxide, rutile ore or ilmenite ore (FeTiO3 There are two main manufacturing methods: the chloride method and the sulfuric acid method, and either method can be used. In addition, in order to improve printability in flexographic printing or gravure printing, it is preferable that the titanium oxide is surface-treated, and in particular, that the titanium oxide is surface-treated with at least one metal selected from the group consisting of Si, Al, Zn, Zr, and oxides thereof.

[0070] The titanium oxide preferably has an oil absorption of 14 to 35 ml / 100 g, more preferably 17 to 32 ml / 100 g, as measured by the method specified in JIS K5101. The titanium oxide preferably has an average particle size (median particle size) of 0.2 to 0.3 μm, as measured by a transmission electron microscope. The total content of the titanium oxide is preferably 1 to 60% by mass, more preferably 10 to 45% by mass, in 100% by mass of the printing ink. Multiple types of titanium oxide may be used in combination.

[0071] <Additives contained in the printing layer> The printing layer of the present invention may contain various additives as required, such as dispersants, waxes, extender pigments, leveling agents, antifoaming agents, and film-forming assistants. Specifically, various additives can be added, such as dispersions of wax resin particles such as polyethylene wax to improve abrasion resistance; extender pigments such as calcium carbonate, kaolin, barium sulfate, aluminum hydroxide, clay, and talc to improve drying properties and coating film hiding properties; inorganic particles and adhesive resins (acrylic resin, vinyl acetate resin) to impart anti-slip properties; leveling agents to improve leveling properties; antifoaming agents to impart antifoaming properties; basic compounds such as sodium hydroxide and potassium hydroxide to impart resolubility; and film-forming aids.

[0072] <Printing ink> The printed layer is preferably formed from a printing ink containing the above-mentioned colorant and the above-mentioned binder resin.

[0073] <Printing ink manufacturing method> The printing ink used to form the printing layer can be produced, for example, by dispersing a pigment in an organic solvent with a resin or the like using a disperser, and mixing the resulting pigment dispersion with a resin, various additives, an organic solvent, and the like. As the disperser, a commonly used one, for example, a roller mill, a ball mill, a pebble mill, an attritor, or a sand mill, can be used. The particle size distribution of the pigment in the pigment dispersion can be adjusted by appropriately adjusting the size of the grinding media of the disperser, the filling rate of the grinding media, the dispersion processing time, the discharge speed of the pigment dispersion, the viscosity of the pigment dispersion, and the like. The viscosity of the printing ink at 25°C is preferably in the range of 50 mPa·s or more from the viewpoint of preventing the pigment from settling and dispersing appropriately, and 300 mPa·s or less from the viewpoint of workability efficiency during ink production and printing. For example, the method described in JP-A-2018-158986 can be used as the method for producing the printing ink.

[0074] <Formation of printing layer> The printing layer can be formed, for example, by printing with a printing ink on the paper substrate surface opposite to the heat seal layer, and then removing the volatile components. The printing method is preferably a flexographic printing method or a gravure printing method, and for example, the ink is diluted with a diluting solvent to a viscosity and concentration suitable for flexographic printing or gravure printing, and is supplied to each printing unit alone or in a mixture and applied. The printing layer can then be obtained by fixing the coating by drying in an oven or the like.

[0075] [Heat seal layer] The heat seal layer in the present invention is located on the paper substrate opposite the surface having the printing layer. The heat seal layer contains a polyethylene-based resin, and the polyethylene-based resin may be a low-density polyethylene resin, a linear low-density polyethylene resin, a medium-density polyethylene resin, a high-density polyethylene resin, an ethylene-vinyl acetate copolymer resin, or an ethylene-acrylic copolymer resin.

[0076] <Formation of heat seal layer> The heat seal layer can be formed, for example, by applying a heat seal agent to the surface of the paper substrate opposite to the printed layer. The heat seal layer containing a polyethylene resin can be formed, for example, by extruding a polyethylene resin that has been thermally melted at 300 to 400°C into a film shape using a slit-shaped device called a T-die, and laminating and coating the film on the paper substrate. It is also possible to form the heat seal layer by applying an ethylene-vinyl acetate copolymer resin and an ethylene-acrylic copolymer resin by flexographic printing or gravure printing. The heat seal layer may contain a component other than a polyethylene resin as long as the main component is a polyethylene resin. Here, the main component being a polyethylene resin means that the content of the polyethylene resin is the highest in the heat seal layer. The heat seal layer preferably contains 80% by mass or more of polyethylene resin, more preferably 90% by mass or more, and even more preferably 95% by mass or more. The thickness of the heat seal layer is preferably 10 to 100 μm, and more preferably 15 to 50 μm.

[0077] [Paper base material] The paper substrate is not particularly limited, and known ones can be used, for example, nonwoven fabric, medium-quality paper, wood-free paper, newsprint, Yupo paper, various coated papers, lining paper, impregnated paper, cardboard, art paper, cast paper, one-sided glossy kraft paper, bleached kraft paper, unbleached kraft paper, coated board, ivory paper, card paper, cup base paper, cast paper, light-shielding paper, and surface-treated paper substrates thereof can be mentioned. In addition, a vapor-deposited paper substrate in which an inorganic compound such as silica, alumina, or aluminum is vapor-deposited on a paper substrate can also be used, and an anchor layer may be used to uniformly form a vapor-deposited layer on the paper substrate, and the vapor-deposited layer may further be coated with polyvinyl alcohol or the like. Furthermore, a paper substrate in which a heat-sealable resin such as polyethylene is formed on the vapor-deposited layer may be used. In addition, various melamine papers in which the paper substrate is impregnated with melamine resin can be used. Among the above, one-sided glossy kraft paper, bleached kraft paper, unbleached kraft paper, and non-coated paper without a coating layer such as a vapor-deposited layer are preferable. The paper base material is 50 to 150 g / m 2 It is preferable that the thickness is 60 to 120 g / m 2 More preferably, the thickness is 60 to 90 g / m 2 It is more preferable that:

[0078] [Barrier layer] The packaging material of the present invention preferably has a barrier layer. When the packaging material has a barrier layer, the barrier layer is preferably located between the paper substrate and the heat seal layer, and an inorganic compound layer can be formed on the paper substrate by a known method such as a vacuum deposition method or a sputtering method. In addition, an aluminum layer can be formed as a barrier layer by laminating an aluminum foil on the paper substrate by a dry lamination method or an extrusion lamination method.

[0079] The barrier layer preferably contains an inorganic compound, and examples of the inorganic compound include, but are not limited to, aluminum, alumina, silica, etc. The purity of the inorganic compound is preferably 99% or more, and more preferably 99.9% or more.

[0080] <Vacuum deposition method> The vacuum deposition method is a method of depositing a metal such as aluminum by high-frequency induction heating, direct current heating, or electron beam heating at 1200 to 1500°C for 10 -1 ~10 -2 This method involves vapor deposition under conditions of about Pa. Prior to vacuum deposition, the object to be deposited may be subjected to a treatment for improving adhesion, such as a corona discharge treatment, on the surface. From the viewpoints of barrier properties, light-shielding properties, and economic efficiency, the thickness of the metal film formed by vacuum deposition is preferably 10 to 300 nm.

[0081] <Sputtering method> The sputtering method is 10 -1 ~10 -2 The deposition is carried out by introducing an inert gas such as Ar and applying a voltage under conditions of about Pa. The thickness of the metal film formed is preferably 10 to 300 nm from the viewpoints of barrier properties, light-shielding properties, and economic efficiency.

[0082] [Adhesive layer] The packaging material of the present invention preferably has an adhesive layer. The adhesive layer can be formed by applying the following adhesive. As the adhesive, a two-liquid reactive adhesive, an acrylic adhesive, an anchor coating agent, a meltable polyolefin resin, etc. are preferably used, but are not limited to these. Among them, it is preferable to form the adhesive layer by a dry lamination method using a two-liquid reactive adhesive, or an extrusion lamination method using an anchor coating agent and a meltable polyolefin resin.

[0083] <Dry lamination method> The dry lamination method is a method of applying a two-liquid reactive adhesive consisting of polyol and polyisocyanate, which is diluted with an organic solvent to an appropriate viscosity, applied to the printed surface of the obtained printed matter, dried, and laminated by pressing with a sealant. Examples of such adhesives include TM-250HV / CAT-RT86L-60, TM-550 / CAT-RT37, and TM-314 / CAT-14B manufactured by Toyo-Morton Co., Ltd.

[0084] <Extrusion lamination method> The extrusion lamination method is a method in which meltable polyolefin resin is extruded into a film form from a slit-shaped device called a T-die, laminated on a substrate, and then bonded to another substrate. In the case of printed matter, an anchor coating agent is often applied to the printed layer before extrusion lamination. Meltable polyolefin resin can also be extruded onto the printed surface of a printed matter and a sealant can be bonded at the same time. As anchor coating agents, imine-based, butadiene-based, and isocyanate-based anchor coating agents can be used. Specific examples include EL-420 (imine-based), EL-452 (butadiene-based), EL-530A / B (isocyanate-based), and EL-540 / CAT-RT32 (isocyanate-based) manufactured by Toyo-Morton Co., Ltd. Meltable polyolefin resins include low-density polyethylene, polypropylene, and ethylene-vinyl acetate copolymers. Specific examples include Novatec LD LC600A (low-density polyethylene) manufactured by Japan Polyethylene Co., Ltd.

[0085] <Manufacturing method of packaging materials> The present invention relates to a method for producing a packaging material having a heat seal layer, a paper base material, a printing layer, and a surface protective layer in this order, the method including the steps of printing a printing ink on one side of the paper base material to form a printing layer, printing an overcoat agent containing an acrylic resin and / or a cellulose-based resin, and a rosin resin on the printing layer to form a surface protective layer, and applying a heat seal agent to the other side of the paper base material to form a heat seal layer. The order of the steps does not matter, but it is preferable to form the printing layer, the surface protective layer, and the heat seal layer in this order.

[0086] The manufacturing method of the packaging material will be described by taking a configuration of a heat seal layer / barrier layer / adhesive resin layer / paper base material / printing layer / surface protection layer as an example. However, the configuration of the packaging material in the present invention is not limited to the above.

[0087] First, the paper base material (unbleached kraft paper: kraft paper made from unbleached kraft pulp (Nippon Paper Industries, unglazed kraft K, basis weight 70 g / m 2) and apply dry lamination adhesive TM-250HV / CAT-RT86L-60 at a rate of 4g / m 2 and then laminating an aluminum foil to form a barrier layer. A polyethylene-based resin is laminated on the barrier layer to form a heat seal layer. Thereafter, a printing ink is flexographically printed or gravure printed on the side of the paper base material that does not have the barrier layer to form a printing layer, and an overcoat agent is flexographically printed or gravure printed to form a surface protective layer, thereby producing a packaging material having a configuration of heat seal layer / barrier layer / adhesive resin layer / paper base material / printing layer / surface protective layer.

[0088] [Packaging bag] The packaging material in the present invention is cut to a predetermined size, and the edges are heat-sealed in a state where the heat-sealable layers are joined together to form a packaging bag. The heat-sealing temperature is preferably 50 to 250°C, and more preferably 80 to 180°C. The heat-sealing pressure is 1 to 5 kg / cm. 2 The conditions are as follows. One sheet of packaging material may be folded and the edges may be heat sealed, or two or more sheets of packaging material may be heat sealed. Also, the packaging bag may be one in which all openings are heat sealed after the contents are packed. This packaging bag can be widely used as a packaging bag for food, medicine, etc. EXAMPLES

[0089] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In the present invention, parts and % represent parts by mass and % by mass unless otherwise noted. In addition, "NV." represents the mass % of non-volatile content.

[0090] <Preparation Example 1> (Preparation of urethane resin solution PU1) In a reactor equipped with a reflux condenser, a dropping funnel, a gas inlet tube, a stirrer, and a thermometer, 227.0 parts of polyester polyol, which is a condensate of adipic acid and 3-methyl-1,5-pentanediol, 9.6 parts of PEG (polyethylene glycol with a number average molecular weight of 2000), 30.1 parts of 2,2-dimethylolpropanoic acid (DMPA), and 250 parts of methyl ethyl ketone (MEK) were mixed and stirred while dropping 90.6 parts of isophorone diisocyanate (IPDI) over 1 hour, and reacted at 80 ° C for 4 hours to obtain a terminal isocyanate prepolymer, and a terminal isocyanate prepolymer solution was obtained. A mixture of 2.7 parts of 2-aminoethylethanolamine (AEA) and 150 parts of isopropanol (IPA) was gradually added to the obtained terminal isocyanate prepolymer solution at room temperature, and reacted at 40 ° C for 2 hours to obtain a solvent-based polyurethane resin solution. Next, 38.1 parts of 10% ammonia water and 801.4 parts of ion-exchanged water were gradually added to the solvent-based polyurethane resin solution to neutralize and make it water-soluble, and then 0.5 parts of an antifoaming agent was added and the MEK and IPA were distilled off under reduced pressure. Water was then added to adjust the solids content, yielding a urethane resin solution PU1 with a solids content of 28% and a weight average molecular weight of 38,000.

[0091] (Printing inks K1 to K6) K1: Printing ink containing styrene-acrylic copolymer resin (acid value 50 mgKOH / g, glass transition temperature 40°C, solid content 48% by mass) K2: Printing ink containing nitrocellulose (weight average molecular weight 30,000, glass transition temperature 120°C) K3: Printing ink containing styrene-maleic acid copolymer resin (acid value 150, glass transition temperature 80°C, solid content 30% by mass) K4: Printing ink containing sugar-derived resin (a styrene-acrylic resin emulsion with an average particle size of 150 μm containing 28% by mass of polysaccharide-derived components, a hydroxyl value of 300 mg KOH / g, an acid value of 50 mg KOH / g, and a solid content of 47% by mass) K5: Printing ink containing rosin resin (rosin resin emulsion, softening point 100°C, hydroxyl value 0 mgKOH / g, acid value 120 mgKOH / g, solid content 50% by mass) K6: Printing ink containing urethane resin (solid content 30%, hydroxyl value 3.8mgKOH / g, amine value 8.5mgKOH / g, weight average molecular weight 48000)

[0092] (Overcoat Agent V1~V9) V1: An overcoat agent containing styrene-acrylic copolymer resin (acid value 100 mgKOH / g, glass transition temperature 20°C, solid content 48% by mass) and rosin resin (acid value 100 mgKOH / g, glass transition temperature 100°C, solid content 50% by mass) in a ratio of 60:40 (mass ratio of solid content). V2: An overcoat agent containing nitrocellulose (weight average molecular weight 30,000, glass transition temperature 120°C) and rosin resin (acid value 10 mgKOH / g, glass transition temperature 100°C, solid content 50% by mass) in a ratio of 60:40 (solid content mass ratio). V3: An overcoat agent containing styrene-acrylic copolymer resin (acid value 100 mgKOH / g, glass transition temperature 20°C, solid content 48% by mass), nitrocellulose (weight average molecular weight 30,000, glass transition temperature 120°C), and rosin resin (acid value 50 mgKOH / g, glass transition temperature 100°C, solid content 50% by mass) in a ratio of 30:30:40 (solid content mass ratio). V4: An overcoat agent containing styrene-acrylic copolymer resin (acid value 100 mgKOH / g, glass transition temperature 20°C, solid content 48% by mass) and rosin resin (acid value 100 mgKOH / g, glass transition temperature 100°C, solid content 50% by mass) at a ratio of 95:5 (solid content mass ratio). V5: An overcoat agent containing styrene-acrylic copolymer resin (acid value 100 mgKOH / g, glass transition temperature 20°C, solid content 48% by mass) and rosin resin (acid value 100 mgKOH / g, glass transition temperature 100°C, solid content 50% by mass) in a ratio of 20:80 (mass ratio of solid content). V6: An overcoat agent containing styrene-acrylic copolymer resin (acid value 100 mgKOH / g, glass transition temperature 20°C, solid content 48% by mass) V7: Overcoat agent containing nitrocellulose (weight average molecular weight 30,000, glass transition temperature 120°C) V8: An overcoat agent containing rosin resin (acid value 100 mgKOH / g, glass transition temperature 100°C, solid content 50% by mass) V9: Overcoat agent containing urethane resin (solid content 30%, hydroxyl value 3.8 mgKOH / g, amine value 8.5 mgKOH / g, weight average molecular weight 48,000)

[0093] (Heat sealant H1~H4) H1: Polyethylene resin (Mitsubishi Chemical Corporation polypropylene resin Novatec PP) H2: Heat sealant containing ethylene vinyl acetate copolymer resin (Japan Coating Resins, Aquatex MC3800, minimum film-forming temperature: 100°C, solid content 50% by mass) H3: Heat sealant containing ethylene acrylic copolymer resin (Japan Coating Resins, Aquatex AC3100, minimum film-forming temperature: 100°C, solid content 44.5% by mass) H4: Heat sealant containing acrylic resin (acid value 100 mgKOH / g, glass transition temperature 20°C, solid content 48% by mass)

[0094] Example 1 (Production of Laminate P1) Next, unbleached kraft paper: kraft paper made from unbleached kraft pulp (manufactured by Nippon Paper Industries Co., Ltd., unbleached kraft K, basis weight 70 g / m 2 ) was printed with printing ink K1 at a printing speed of 50 m / min using a small flexiproof printer (flexographic printer) equipped with a 250 line / inch anilox roll and a solid plate made of photosensitive resin, and then dried for 10 seconds with a 1200 W dryer to form a printed layer. Overcoat agent V1 was printed on the printed layer at a printing speed of 50 m / min using a small flexiproof printer (flexographic printer) equipped with a 200 line / inch anilox roll and a solid plate made of photosensitive resin, and then dried at 25°C for 12 hours to obtain an intermediate laminate p1 having a paper substrate / printed layer / surface protective layer configuration. Aluminum foil was laminated to the side of the substrate opposite the printed layer in the intermediate laminate p1 by extrusion lamination under conditions of adhesive resin: polyethylene (melting point: 120°C), resin temperature: 330°C, coating speed: 80 m / min, coating thickness: 10 μm. Polyethylene resin (melting point: 120°C) was then coated onto the aluminum foil under conditions of resin temperature: 330°C, coating speed: 80 m / min, coating thickness: 20 μm, to obtain a packaging material P1 having a composition of heat seal layer / barrier layer / adhesive resin layer / paper substrate / printed layer / surface protection layer.

[0095] <Examples 2 to 15, Comparative Examples 1 to 6> (Production of packaging materials P2 to 15, P'1 to 6) The heat seal layers of the packaging material other than P1 were formed by printing a heat seal agent using a gravure printing machine equipped with a gravure plate with a plate depth of 50 μm, at a printing speed of 50 m / min and an in-line oven temperature of 70° C. Otherwise, the printing inks, overcoat agents, and heat seal agents shown in Tables 1 and 2 were used to prepare packaging materials P2 to 15 and P'1 to 6 having the same configuration as the packaging material P1, using the same procedure as in the preparation of the packaging material P1. The paper used was Marie Coat paper.

[0096] [Evaluation of packaging materials] The packaging materials P1 to 15 and P'1 to 6 obtained in Examples 1 to 15 and Comparative Examples 1 to 6 will be described below. The evaluations described in were carried out. The results are shown in Tables 1 and 2. For the Examples and Comparative Examples other than Comparative Example 2 which did not have a surface protective layer, the 60 degree gloss value of the surface protective layer was measured by the method described in JIS Z8741:1997.

[0097] <Water friction resistance> The obtained packaging material was cut into a size of 25 mm x 150 mm, and the water friction resistance was evaluated according to the following criteria using a Gakushin-type friction fastness tester manufactured by Tester Sangyo Co., Ltd. Note that A, B, and C are ranges that are acceptable for practical use. Test conditions Load: 200g, number of reciprocations: 2, paper: 5 drops of water on Kanakin cloth Evaluation Criteria A. The printed layer is not removed and the exposed area of ​​the base paper is less than 1%. B. The paper has a small amount of ink on it. A small amount of the printing layer has been removed, and the exposed area of ​​the base paper is between 1% and 10%. C. The paper has a thin layer of ink on the entire surface. The printed layer has been removed slightly, and the exposed area of ​​the base paper is between 10% and 20%. D. The ink is thickly adhered to the entire surface of the paper. Most of the printing layer has been removed, and the exposed area of ​​the base paper is 20% or more.

[0098] <Heat resistance> The obtained packaging material was cut into a size of 25 mm x 150 mm, and a glossy aluminum foil (thickness: 15 μm) of 25 mm x 150 mm was placed on the surface protective layer, and heat-sealed using the following device and conditions. After peeling off the aluminum foil, the heat resistance was evaluated based on the state of the printed layer according to the following criteria. A, B, and C are ranges that are practically acceptable. <Heat sealing conditions> Equipment: Thermal gradient heat sealer [Toyo Seiki Co., Ltd.; TYPE, HG-100], Seal width: 10mm from the bent part, heater temperature: 160℃, Sealing pressure: 2kg / cm 2 , Sealing time: 1sec Evaluation Criteria A. The printed layer is not removed and the exposed area of ​​the base paper is less than 1%. B. The paper has a small amount of ink on it. A small amount of the printing layer has been removed, and the exposed area of ​​the base paper is between 1% and 10%. C. The paper has a thin layer of ink on the entire surface. The printed layer has been removed slightly, and the exposed area of ​​the base paper is between 10% and 20%. D. The ink is thickly adhered to the entire surface of the paper. Most of the printing layer has been removed, and the exposed area of ​​the base paper is 20% or more.

[0099] <Releasability> The obtained packaging material was cut into two pieces of 40 mm square, and the heat seal layer and the surface protection layer of the cut packaging material were overlapped, and the material was pressed at a temperature of 40°C and a load of 100 kg / cm using a small heat press machine H30-10D manufactured by AS ONE Corporation. 2 (meaning a significantly excessive load). After leaving it in that state for 12 hours, the two overlapping prints were peeled off, and the peeling state of the print layers was visually observed and evaluated according to the following criteria. A, B, and C are ranges that are acceptable for practical use. Evaluation Criteria A. The amount of the printed layer transferred to the back side of the unbleached kraft paper is less than 1% by area. B. The amount of the printed layer transferred to the back surface of the unbleached kraft paper is 1 area % or more and less than 10 area %. C. The amount of the printed layer transferred to the back surface of the unbleached kraft paper is 10 area % or more and less than 20 area %. D. The amount of the printed layer transferred to the back side of the unbleached kraft paper is 20% or more by area.

[0100] <Water vapor barrier properties> The resulting packaging material was measured for moisture permeability according to JIS Z0208, and the water vapor barrier property was evaluated based on the results according to the following criteria, where A, B, and C are ranges that are acceptable for practical use. Evaluation conditions: Evaluation time: 15 hours Evaluation Criteria A. Moisture permeability is 5g / m 2 Less than 15 hours. B. Moisture permeability is 5g / m 2 ·15h or more, 1000g / m 2 Less than 15 hours. C. Moisture permeability is 1000g / m 2 ·15h or more, 3000g / m 2 Less than 15 hours. D. Moisture permeability is 3000g / m 2 -15 hours or more.

[0101] <Heat sealability> The obtained packaging material was cut into a size of 15 mm x 100 mm, folded so that the heat-sealed layers overlapped each other, and heat-sealed using the following equipment and conditions. Both unsealed ends were fixed to a small tensile tester to evaluate the heat-seal strength. A, B, and C are ranges that are acceptable for practical use. <Heat sealing conditions> Equipment: Heat seal tester manufactured by Tester Sangyo Co., Ltd., Seal width: from the folded part 10mm, heater temperature: 160℃, sealing pressure: 2kg / cm 2 , Sealing time: 1sec <Heat seal strength measurement conditions> Equipment: Intesco small tensile testing machine (model: IM-20), test piece width: 15 mm, peeling mode: 90° peeling, tensile speed: 300 mm / min Evaluation Criteria A. The heat seal strength is 5.0N or more. B. The heat seal strength is greater than or equal to 3.5N and less than 5.0N. C. The heat seal strength is 1.0N or more and less than 3.5N. D. The heat seal strength is less than 1.0 N.

[0102] [Table 1]

[0103] [Table 2]

[0104] The present invention provides a packaging material that is excellent in water friction resistance, heat resistance, releasability, water vapor barrier property, and heat sealability. In particular, in Comparative Example 3, in which the surface protective layer contained an acrylic resin, the water friction resistance did not meet the standard, and in Comparative Example 4, in which the surface protective layer contained a cellulose-based resin, Comparative Example 5, in which the surface protective layer contained a rosin resin, and Comparative Example 6, in which the surface protective layer contained a urethane resin, the release properties did not meet the standard.

Claims

1. A packaging material having a heat-seal layer, a paper substrate, a printing layer, and a surface protection layer in that order, and further including a barrier layer, A packaging material wherein the surface protective layer comprises at least one selected from the group consisting of acrylic resin and cellulose resin, and rosin resin.

2. The packaging material according to claim 1, wherein the 60-degree gloss value of the surface protective layer, measured by the method described in JIS Z 8741:1997, is 60 or less.

3. The packaging material according to claim 1 or 2, wherein the mass ratio of acrylic resin and cellulose resin to rosin resin is 90:10 to 30:

70.

4. The packaging material according to claim 1 or 2, wherein the heat-seal layer contains a polyethylene resin.

5. The packaging material according to claim 4, wherein the polyethylene resin comprises at least one selected from the group consisting of ethylene vinyl acetate copolymer resin and ethylene acrylic copolymer resin.

6. The packaging material according to claim 1 or 2, wherein the printing layer comprises at least one selected from the group consisting of cellulose resin, acrylic resin, and styrene-maleic acid copolymer resin.

7. The packaging material according to claim 1 or 2, wherein the printed layer comprises a sugar-derived resin and / or rosin resin.

8. A packaging bag formed from the packaging material described in claim 1 or 2.

9. A method for manufacturing a packaging material having a heat-seal layer, a paper substrate, a printing layer, and a surface protection layer in that order, and further including a barrier layer, A method for manufacturing packaging material, comprising the steps of: forming a barrier layer by lamination, vapor deposition, or sputtering; forming a printed layer by printing printing ink on one side of a paper substrate; forming a surface protective layer by printing an overcoat agent containing at least one selected from the group consisting of acrylic resin and cellulose-based resin and rosin resin onto the printed layer; and forming a heat seal layer by applying a heat seal agent to the other side of the paper substrate.

10. A method for manufacturing a packaging material according to Claim 9, A method for manufacturing packaging material, wherein the 60-degree gloss value of the surface protective layer, as measured by the method described in JIS Z 8741:1997, is 60 or less.